Electronic device, power control method and storage medium storing program thereof

ABSTRACT

In an electronic device, a first sensor detects a detection target on a first region. A second sensor detects a detection target on a second region. A third sensor detects a detection target on a third region. A power control unit turns on the second sensor in a case where the first sensor detects the detection target on the first region. The power control unit turns on the third sensor and turns off the first sensor in a case where the second sensor detects the detection target on the second region.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to an electronic device having a pluralityof sensors used to detect movement of an external detection target, apower control method, and a storage medium storing a program thereof.

Description of the Related Art

A detection system which detects a change in sensing target as a timeseries using a plurality of sensors is known. For example, two infraredsensors which detect the presence of a heat source such as a person areprepared at points A and B, and detection times of the sensors at thepoints A and B are overlaid to detect movement of a person as adetection target from the point A to the point B. In this arrangement,as the number and types of sensors are increased, detection can be madeat higher precision.

Japanese Patent Laid-Open No. 2012-087962 describes an arrangement whichcombines a sensor which can detect a broad range at a low resolution,and a sensor which can detect a narrow range at a high resolution. Inthis arrangement, after an access of a person is detected by the formersensor, an azimuth direction in which the person exists practically isdetected using the latter sensor, the azimuth direction in which theperson exists can be precisely detected using a small number of sensors.

In general, to a sensor, a power supply line for the sensor and adetection signal line used to notify a CPU or the like of detection areconnected. As the number of sensors in a system increases, the number ofdetection signal lines is also increased, thus consuming I/O ports ofthe CPU as the notification destination. Also, total power consumptionconsumed by the sensors in the whole system is also increased. However,even when power supply lines are configured to power only requiredsensors, these power supply lines further unwantedly consume I/O portsof the CPU.

However, in the power control arrangement required to power onlyrequired sensors, the CPU has to always be in an operating state.Therefore, when the power consumption of the CPU is large, electricpower which can be reduced by turning off a power source of unnecessarysensors by the power control may be canceled out. Also, even when thepower control is configured to be executed via a dedicated IC integratedcircuit) or encoder/decoder in place of the CPU, the detection system ismore complicated.

SUMMARY OF THE INVENTION

An aspect of the present invention is to eliminate the above-mentionedproblems with the conventional technology. The present inventionprovides an electronic device which detects a detection target using aplurality of sensors and reduces power consumption, a power controlmethod, and a storage medium storing a program thereof.

The present invention in a first aspect provides an electronic devicecomprising: a first sensor configured to detect a detection target on afirst region; a second sensor configured to detect a detection target ona second region; a third sensor configured to detect a detection targeton a third region; and a power control unit configured to turn on thesecond sensor in a case where the first sensor detects the detectiontarget on the first region, and configured to turn on the third sensorand to turn off the first sensor in a case where the second sensordetects the detection target on the second region.

The present invention in a second aspect provides a power control methodexecuted in an electronic device, which has a first sensor configured todetect a detection target on a first region, a second sensor configuredto detect a detection target on a second region, and a third sensorconfigured to detect a detection target on a third region, the methodcomprising: turning on the second sensor in a case where the firstsensor detects the detection target on the first region; and turning onthe third sensor and turning off the first sensor in a case where thesecond sensor detects the detection target on the second region.

The present invention in a third aspect provides a computer-readablemedium that stores therein a program of a power control method executedin an electronic device, which has a first sensor configured to detect adetection target on a first region, a second sensor configured to detecta detection target on a second region, and a third sensor configured todetect a detection target on a third region, the program for causing acomputer to: turn on the second sensor in a case where the first sensordetects the detection target on the first region; and turn on the thirdsensor and turning off the first sensor in a case where the secondsensor detects the detection target on the second region.

According to the present invention, power consumption can be reduced inthe electronic device which detects a detection target using a pluralityof sensors.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing the arrangement of a detection system;

FIG. 2 is a view showing the internal arrangement of each sensor;

FIG. 3 is a view showing detection ranges of sensors;

FIGS. 4A and 4B are flowcharts showing the sequence of power controlprocessing executed when a person comes closer according to the firstembodiment;

FIGS. 5A and 5B are flowcharts showing the sequence of the power controlprocessing executed when a person moves away;

FIG. 6 is a table showing power ON/OFF states of respective unitsaccording to positions of a person;

FIG. 7 is a block diagram showing the arrangement of a detection systemaccording to the second embodiment;

FIGS. 8A and 8B are flowcharts showing the sequence of power controlprocessing executed when a person comes closer according to the secondembodiment;

FIGS. 9A and 9B are flowcharts showing the sequence of the power controlprocessing executed when a person moves away; and

FIG. 10 is a table showing power ON/OFF states of respective unitsaccording to positions of a person.

DESCRIPTION OF THE EMBODIMENTS

Preferred embodiments of the present invention will now be describedhereinafter in detail, with reference to the accompanying drawings. Itis to be understood that the following embodiments are not intended tolimit the claims of the present invention, and that not all of thecombinations of the aspects that are described according to thefollowing embodiments are necessarily required with respect to the meansto solve the problems according to the present invention. Note that thesame reference numerals denote the same components, and a descriptionthereof will not be repeated.

First Embodiment

FIG. 1 is a block diagram showing the arrangement of a detection system101 which can detect movement of a detection target such as a personoutside a device using a plurality of sensors. In this embodiment, adetection system 101 is mounted in an image processing apparatusrepresented by a printer, scanner, or MFP which integrates theseplurality of functions. The image processing apparatus will also besimply referred to as an electronic device hereinafter as a deviceincluding the detection system 101. The detection system 101 includes acontroller 102, three types of sensors, that is, first sensor 103,second sensor (intermediate sensor) 104, and third sensor (final sensor)105, power source unit 106, main switch 107, and AC outlet 108. Thecontroller 102 includes a CPU 121, a RAM 122 which is used as atemporary storage by the CPU 121, and a ROM 123 which stores variousprograms executed by the CPU 121. When a power source of the CPU 121 isturned on, the CPU 121 loads programs from the ROM 123 onto the RAM 122to implement functions of the image processing apparatus which mountsthe detection system 101. The image processing apparatus can resume froma power saving mode to a normal mode when it detects an access of aperson by the detection system 101, and can set the power saving modeupon detection of the absence of a person. The sensors used in thisembodiment are those which can detect the presence of a detection targetsuch as an external person, and may include, for example, an infraredsensor and pyroelectric sensor. Since the respective sensors havedifferent detection regions, movement of the detection target, that is,whether or not the detection target comes closer to or moves away fromthe image processing apparatus can be detected. The detection regions ofthe sensors will be described later with reference to FIG. 3.

To the first sensor 103, a detection signal line 131 and sensor powersupply line 171 are connected. To the intermediate sensor 104, adetection signal line 141 and sensor power supply line 181 areconnected. To the final sensor 105, a detection signal line 151 andsensor power supply line 191 are connected. Note that the detectionsignal lines 131, 141, and 151 are connected to detection signal outputterminals of the corresponding sensors. Also, the sensor power supplylines 171, 181, and 191 are connected to power source terminals of thecorresponding sensors. The sensor power supply lines 171, 181, and 191are respectively connected to output terminals of sensor power sourcerelays 132, 142, and 152 required to open/close switches used to supplyelectric power.

The detection signal line 131 is connected to an input terminal of anAND circuit 193. Also, a senor power control line 124 from the CPU 121is connected to an inverting input terminal of the AND circuit 193. Anoutput terminal of the AND circuit 193 is connected to an enableterminal of the sensor power source relay 142. The detection signal line141 is connected to an enable terminal of the sensor power source relay152 and that of a main power source 161 in a power source unit 106. Thedetection signal line 151 is connected to a reset terminal of the CPU121, and is also connected to an inverting input terminal of an ANDcircuit 192. An output signal line of the main switch 107 as a mainpower source switch of the detection system 101 is connected to an inputterminal of the AND circuit 192, and an output terminal of the ANDcircuit 192 is connected to an enable terminal of the sensor powersource relay 132. Statuses of detection signals output from the sensors103 to 105 onto the detection signal line and a status of the sensorpower control line 124 output from the CPU 121 are latched by latchcircuits (not shown) in respective devices independently of power sourcestatuses of the respective devices.

The power source unit 106 includes the main power source 161 and a subpower source 162. The main power source 161 is, for example, an AC/DCconverter power source module, which generates electric power for thecontroller 102, and a power supply line is connected to the controller102. Also, as described above, to the enable terminal of the main powersource 161, the detection signal line 141 from the intermediate sensor104 is connected. When the enable terminal of the main power source 161is activated, the main power source 161 can supply electric power to thecontroller 102.

The sub power source 162 is, for example, an AC/DC converter powersource module, which generates electric power to be supplied to therespective sensors. A power supply line of the sub power source 162 isconnected to the sensor power source relays 132, 142, and 152. When anenable terminal of the sub power source 162 is activated, the sub powersource 162 can supply electric power to the sensor power source relays132, 142, and 152. The output signal line of the main switch 107 is alsoconnected to the enable terminal of the sub power source 162. When themain switch 107 is turned on, the enable terminal of the sub powersource 162 is activated. When the enable terminals of the sensor powersource relays 132, 142, and 152 are activated, the electric powersupplied from the sub power source 162 can be further supplied to thecorresponding sensors 103 to 105. The AC outlet 108 supplies AC electricpower to the main power source 161 and sub power source 162. In a normaloperation mode in which electric power is supplied to respective unitsof the image processing apparatus which mounts the detection system 101,the enable terminal of the main power source 161 is active. Also, in apower saving mode in which power supply in the image processingapparatus is limited compared to the normal operation mode, the enableterminal of the main power source 161 is inactive, and the enableterminal of the sub power source 162 is active.

FIG. 2 shows the internal arrangement of the sensors 103 to 105. Each ofthe sensors 103 to 105 includes a detection unit 201 including alight-emitting unit 202 and light-receiving unit 203, a detection signalline 204, and a power supply line 205. In this case, the detectionsignal line 204 corresponds to the detection signal lines 131, 141, and151 shown in FIG. 1. Also, the power supply line 205 corresponds to thepower supply lines 171, 181, and 191 shown in FIG. 1. The light-emittingunit 202 includes an infrared LED, and radiates infrared rays. Thelight-receiving unit 203 detects infrared rays. When a detection targetsuch as a person exists within a detection range of the sensor, infraredrays radiated from the light-emitting unit 202 are reflected by thedetection target, and the light-receiving unit 203 detects the reflectedinfrared rays. Upon detection of the reflected infrared rays, thelight-receiving unit 203 activates the detection signal line 204. Withthis arrangement, each of the sensors 103 to 105 can notify a unitoutside the sensor of detection of the detection target via thedetection signal line 204. The power supply line 205 connected to thedetection unit 201 is connected to the light-emitting unit 202 andlight-receiving unit 203, and the detection unit 201 operates whenelectric power is supplied from the power supply line 205.

The power control processing of the respective sensors in the detectionsystem 101 will be described below with reference to FIGS. 1, 3, 4A, 4B,5A, 5B, and 6.

FIG. 3 shows detection ranges of the first sensor 103, intermediatesensor 104, and final sensor 105. The detection regions of the sensorsare that of the first sensor 103, that of the intermediate sensor 104,and that of the final sensor 105 in an order farther from the imageprocessing apparatus which mounts the detection system 101. A detectionregion 301 of the first sensor 103 and a detection region 302 of theintermediate sensor 104 partially overlap each other. Also, thedetection region 302 of the intermediate sensor 104 and a detectionregion 303 of the final sensor 105 partially overlap each other.

A case will be described first wherein a detection target such as aperson comes closer from a point A to the image processing apparatuswhich mounts the detection system 101. FIGS. 4A and 4B are flowchartsshowing the sequence of the power control processing of the detectionsystem 101 when the target comes closer.

In an initial state of the detection system 101, all of the detectionsignal lines 131, 141, and 151 are inactive. When the main switch 107 isturned on, only a power source of the first sensor 103 is turned on bythe main switch 107. As a result, the first sensor 103 starts scanningof a detection target in the detection region 301 (step S401). In thiscase, the AND circuit 192 activates the enable terminal of the sensorpower source relay 132 based on the inverting input of the inactivedetection signal 151 and the active output signal line from the mainswitch 107. Also, since the detection signal lines 131 and 141 areinactive, the enable terminals of the sensor power source relays 142 and152 are inactive. Therefore, no electric power is supplied to theintermediate sensor 104 and final sensor 105.

In step S402, the first sensor 103 is set in a state of whether or notto detect a detection target. When a detection target at the point Ashown in FIG. 3 moves into the detection region 301, and the firstsensor 103 detects the detection target (YES in step S402), the firstsensor 103 activates the detection signal line 131 (step S403). Notethat the processes in step S403 and subsequent steps are executed whenthe first sensor 103 detects the detection target in step S402.

When the detection signal line 131 is activated, the output of the ANDcircuit 193 is activated by the active detection signal line 131 and theinactive sensor power control line 124 from the CPU 121, thus activatingthe enable terminal of the sensor power source relay 142. As a result,the sensor power source relay 142 is closed, and electric power issupplied to the intermediate sensor 104 (step S404). Then, theintermediate sensor 104 starts scanning of a detection target within thedetection region 302 (step S405).

In step S406, the intermediate sensor 104 is set in a state of whetheror not to detect a detection target. When the detection target movesinto the detection region 302, and the intermediate sensor 104 detectsthe detection target (YES in step S406), the intermediate sensor 104activates the detection signal line 141 (step S407). Note that theprocesses in step S407 and subsequent steps are executed when theintermediate sensor 104 detects the detection target in step S406.

When the detection signal line 141 is activated, it activates the enableterminal of the sensor power source relay 152. As a result, the sensorpower source relay 152 is closed, and electric power is supplied to thefinal sensor 105 (step S408). Then, the final sensor 105 starts scanningof a detection target within the detection region 303 (step S409).

Parallel to the aforementioned steps, since the detection signal line141 activates the enable terminal of the main power source 161, the mainpower source 161 supplies electric power to the controller 102 (stepS410). As a result, the controller 102 is powered (step S411). Since thecontroller 102 is powered, the CPU 121 autonomously loads data from theROM 123 onto the RAM 122, executes the loaded data, and stands by in areset state (step S412).

In step S413, the final sensor 105 is set in a state of whether or notto detect a detection target. When the detection target moves into thedetection region 303, and the final sensor 105 detects the detectiontarget (YES in step S413), the final sensor 105 activates the detectionsignal line 151 (step S414). Note that the processes in step S414 andsubsequent steps are executed when the final sensor 105 detects thedetection target in step S413.

After the detection signal line 151 is activated, the CPU 121 detectsthe active detection signal line 151, and cancels the reset state (stepS415). Parallel to this step, the output of the AND circuit 192 isinactivated. As a result, the sensor power source relay 132 is opened tocut off power supply to the first sensor 103 (step S416). Note that thedetection signal lines of the respective sensors are latched by latchcircuits (not shown), as described above. Therefore, even when powersupply to the first sensor 103 is cut off, the detection signal line 131holds the active state.

Next, the CPU 121 executes operation preparation (step S417), and it isdetermined whether or not the CPU 121 is set in an operating state (stepS418). Note that in the operating state, for example, respectivefunctions such as a print function of the image processing apparatuswhich mounts the detection system 101 are ready to be executed. Theprocesses in step S419 and subsequent steps are executed when it isdetermined that the CPU 121 is set in the operating state in step S418.If it is determined in step S418 that the CPU 121 is in the operatingstate, the CPU 121 activates the sensor power control line 124 (stepS419). Then, the output of the AND circuit 193 is inactivated. As aresult, the sensor power source relay 142 is opened to cut off powersupply to the intermediate sensor 104 (step S420).

A case will be described below wherein a detection target moves awayfrom the detection system 101 toward the point A. In this case, theinitial state of the detection system 101 is premised on that theprocessing shown in FIGS. 4A and 4B has already been executed.Therefore, the detection signal lines of all the sensors are latched inan active state.

When the detection target completes use of the print function or thelike of the image processing apparatus which mounts the detection system101, the CPU 121 executes halt preparation processing (step S501) todetermine whether or not the apparatus enters a halt state (step S502).Note that in the halt state, for example, neither an external operationnor instruction is input to the image processing apparatus which mountsthe detection system 101. In this case, for example, when a state inwhich no external operation is input continues for a predeterminedperiod of time, the CPU 121 may start halt preparation. The processes ofstep S503 and subsequent steps are executed when it is determined instep S502 that the apparatus is in the halt state. If it is determinedin step S502 that the apparatus is in the halt state, the CPU 121inactivates the sensor power control line 124 (step S503). As a result,the sensor power source relay 142 is closed to power the intermediatesensor 104 (step S504).

The final sensor 105 scans the detection target in the detection region303 in step S505, and is set in a state of whether or not to detect thedetection target in step S506. When the detection target moves away fromthe detection region 303 and moves into the detection region 302, andthe final sensor 105 ceases to detect the detection target (YES in stepS506), the final sensor 105 inactivates the detection signal line 151(step S507). When the detection signal line 151 is inactivated, thesensor power source relay 132 is closed to power the first sensor 103(step S508). Parallel to this step, the inactive detection signal line151 inactivates the reset terminal of the CPU 121 (step S509). As aresult, the CPU 121 is reset (step S510).

The intermediate sensor 104 scans the detection target within thedetection region 302 in step S511, and is set in a state of whether ornot to detect the detection target in step S512. When the detectiontarget moves away from the detection region 302 and moves into thedetection region 301, and the intermediate sensor 104 ceases to detectthe detection target (YES in step S512), the intermediate sensor 104inactivates the detection signal line 141 (step S513). Since thedetection signal line 141 is inactivated, the sensor power source relay152 is opened to cut off power supply to the final sensor 105 (stepS514). Parallel to this step, the enable terminal of the man powersource 161 is inactivated, and the main power source 161 stops powersupply to the controller 102 (step S515). As a result, the controller102 stops its operation (step S516). As described above, since thesensors 103 to 105 have latch circuits (not shown), the detection signalline 151 and sensor power control line 124 are held inactive.

The first sensor 103 scans the detection target in the detection region301 in step S517, and is set in a state of whether or not to detect thedetection target in step S518. When the detection target moves away fromthe detection region 301 and moves to the point A, and the first sensor103 ceases to detect the detection target (YES in step S518), the firstsensor 103 inactivates the detection signal line 131 (step S519). Sincethe detection signal line 131 is inactivated, the sensor power sourcerelay 142 is opened to cut off power supply to the intermediate sensor104 (step S520). Also, by latch circuits (not shown), the detectionsignal line 141 is held inactive.

FIG. 6 is a table showing the relationship between the positions of thedetection target and power-on states of the sensors 103 to 105 andcontroller 102. FIG. 6 shows a state in which the power-on states of thesensors 103 to 105 and controller 102 are sequentially switchedaccording to the positions of the detection target. For example, as thedetection target comes from the point A closer to the detection system101, power-on blocks gradually transition from the first sensor 103alone in the power-on state until the power-on state of the controller102. The same applies to a case in which the detection target moves awayfrom the detection system 101 toward the point A.

As described above, according to this embodiment, electric power can besupplied to only sensors involved in detection depending on the locationof the detection target. In this embodiment, sensors independentlycontrol power sources of other sensors. For this reason, the CPU 121need not be in an operating state for sensor power control. Furthermore,since only the detection signal line 151 of the final sensor 105 isconnected to the reset terminal of the CPU 121, I/O ports of the CPU 121as many as the number of sensors need not be assured unlike in therelated art when a plurality of sensors are arranged.

Also, this embodiment has explained the three types of sensors, that is,the first sensor 103, intermediate sensor 104, and final sensor 105.However, even when the number of intermediate sensors 104 is increased,the control of the intermediate sensor 104 of this embodiment isrepetitively executed to implement the same processes shown in FIGS. 4and 5.

Second Embodiment

The first embodiment has explained the case in which a power source of acontroller 102 is OFF in an initial state, and a CPU 121 begins tooperate as a detection target comes closer to an image processingapparatus which mounts a detection system 101. However, even when thecontroller 102 stands by in a power saving state, the processes of FIGS.4 and 5 are applicable. Differences from the first embodiment will bedescribed below in association with a case in which the controller 102stands by in the power saving state.

FIG. 7 is a block diagram showing the arrangement of the detectionsystem 101 according to this embodiment. Unlike in FIG. 1, a powersupply line from a sub power source 162 is also supplied to the CPU 121.Connection of the power supply line to the CPU 121 is indicated by apower supply line 701 in FIG. 7. In this embodiment, when the controller102 stands by in the power saving state, electric power is supplied froma sub power source 162 via the power supply line 701. On the other hand,when the controller 102 transitions to a normal operation state,electric power is supplied from the main power source 161.

Power control processing in the detection system 101 which includes aplurality of sensors and the controller 102 having the power savingstate will be described below with reference to FIGS. 3, 7, 8A, 8B, 9Aand 9B. A case will be explained first wherein a detection target comesfrom a point A closer to the detection system 101. FIGS. 8A and 8B areflowcharts showing the sequence of the power control processing executedwhen the detection target comes from the point A closer to the detectionsystem 101. FIGS. 8A and 8B are different from FIGS. 4A and 4B in thatstep S801 is executed after step S411.

When the detection target moves from a detection region 301 to adetection region 302, and an intermediate sensor 104 detects thedetection target (YES in step S406), a detection signal line 141activates an enable terminal of the main power source 161. Then, themain power source 161 supplies electric power to the controller 102(step S410). As a result, electric power is supplied from the main powersource 161 to the controller 102 (step S411), and the controller 102transitions from the power saving state to the normal operation state(step S801).

A case will be described below wherein the detection target moves awayfrom the detection system 101 toward the point A. FIGS. 9A and 9B areflowcharts showing the sequence of the power control processing executedwhen the detection target moves away from the detection system 101toward the point A. FIGS. 9A and 9B are different from FIGS. 5A and 5Bin that step S901 is executed after step S515.

That is, when the detection target is located within the detectionregions 303 and 302, the same processing as in the first embodiment isexecuted. When the detection target further moves into the detectionregion 301, and the intermediate sensor 104 ceases to detect thedetection target (YES in step S512), the intermediate sensor 104inactivates the detection signal line 141 to stop power supply from themain power source 161 (step S515). As a result, since electric power issupplied from only the sub power source 162 to the controller 102, thecontroller 102 autonomously transitions to the power saving state (stepS901).

As described above, according to this embodiment, even when thecontroller 102 has the power saving state, only sensors involved indetection of the detection target can be powered.

FIG. 10 is a table showing the relationship between the positions of thedetection target and power-on states of the sensors 103 to 105 andcontroller 102. FIG. 10 shows a state in which the power-on states ofthe sensors 103 to 105 and controller 102 are sequentially switchedaccording to the positions of the detection target. For example, whenthe detection target comes closer to the detection system 101, thecontroller 102 is switched from the power saving state to the normaloperation state when the detection target is located within thedetection region 302.

As described in the first and second embodiments, since the sensorsexecute power control of other sensors upon movement of the detectiontarget, electric power can be supplied to only required sensors, thusreducing the power consumption of the overall detection system. Also,since the sensors execute power control of other sensors, power controloutput ports for all the sensors need not be assured for the CPU, andthe number of ports of the CPU can be saved. Furthermore, since the CPUis not involved in power control of all the sensors, the powerconsumption of the CPU can be suppressed to be as low as possible.

Other Embodiments

Embodiments of the present invention can also be realized by a computerof a system or apparatus that reads out and executes computer executableinstructions recorded on a storage medium (e.g., non-transitorycomputer-readable storage medium) to perform the functions of one ormore of the above-described embodiment(s) of the present invention, andby a method performed by the computer of the system or apparatus by, forexample, reading out and executing the computer executable instructionsfrom the storage medium to perform the functions of one or more of theabove-described embodiment(s). The computer may comprise one or more ofa central processing unit (CPU), micro processing unit (MPU), or othercircuitry, and may include a network of separate computers or separatecomputer processors. The computer executable instructions may beprovided to the computer, for example, from a network or the storagemedium. The storage medium may include, for example, one or more of ahard disk, a random-access memory (RAM), a read only memory (ROM), astorage of distributed computing systems, an optical disk (such as acompact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™),a flash memory device, a memory card, and the like.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Application No.2013-055418, filed Mar. 18, 2013, which is hereby incorporated byreference herein in its entirety.

1-7. (canceled)
 8. An electronic device comprising: a first sensor fordetecting a detection target in a first region; a second sensor fordetecting a detection target in a second region; a third sensor fordetecting a detection target in a third region; and a power controllerconfigured to turn on the second sensor in a case where the first sensordetects the detection target in the first region, and turn on the thirdsensor and turn off the first sensor in a case where the second sensordetects the detection target in the second region.
 9. The deviceaccording to claim 8, wherein the power controller controls theelectronic device to transit to a normal operation mode from a powersaving mode in a case where the second sensor detects the detectiontarget in the second region.
 10. The device according to claim 8,wherein the power controller turns off the second sensor, in a casewhere the first sensor detects the detection target in the first regionafter the second sensor detects the detection target in the secondregion.
 11. The device according to claim 10, wherein the powercontroller controls the electronic device to transit to a power savingmode from a normal operation mode, in a case where the first sensordetects the detection target in the first region after the second sensordetects the detection target in the second region.
 12. The deviceaccording to claim 8, wherein the power controller comprises a switchwhich is connected to the second sensor and is for turning on or off thesecond sensor, and the switch is configured to open or close a powersupply line to the second sensor using a detection signal line of thefirst sensor.
 13. A power control method for an electronic device thatincludes a first sensor for detecting a detection target in a firstregion, a second sensor for detecting a detection target in a secondregion, and a third sensor for detecting a detection target in a thirdregion, the method comprising: turning on the second sensor in a casewhere the first sensor detects the detection target in the first region,and turning on the third sensor and turning off the first sensor in acase where the second sensor detects the detection target in the secondregion.
 14. A non-transitory computer-readable storage medium storing aprogram for controlling an electronic device that includes a firstsensor for detecting a detection target in a first region, a secondsensor for detecting a detection target in a second region, and a thirdsensor for detecting a detection target in a third region, the programcausing a computer to: turn on the second sensor in a case where thefirst sensor detects the detection target in the first region, and turnon the third sensor and turn off the first sensor in a case where thesecond sensor detects the detection target in the second region.